std::shared_ptr<void> foo(nullptr, [&bar] (void*) { printf(":) %s\n", bar); }); the downside is having to write nullptr instead of just the closure. Something

std::shared_ptr<void> foo(nullptr, [&bar] (void*) { printf(":) %s\n", bar); }); the downside is having to write nullptr instead of just the closure. Something like this really should be part of the standard.